Q.12 Cost of a dozen pens is Rs 180 and cost of 8 ball pens is Rs 56. Find the ratio of the cost of a pen to the cost of a ball pen.

Cost of a dozen pens = Rs 180
Cost of 1 pen = \(\frac{180}{12} = Rs 15 \)
Cost of 8 ball pens = Rs 56
Cost of 1 ball pen = \(\frac{56}{8} = Rs 7 \)
Hence, required ratio is = 15 : 7